Investment Securities (Schedule Of Investment Securities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	$ 801,147	$ 1,274,258
Securities Available-for-Sale, Gross Unrealized Holdings Gains	19,530	34,740
Securities Available-for-Sale, Gross Unrealized Holding Losses	32	11,476
Securities Available-for-Sale, Estimated Fair Value	820,645	1,297,522
Securities Held-to-Maturity, Amortized Cost	820,224	673,570
Securities Held-to-Maturity, Gross Unrealized Holding Gains	14,382	17,164
Securities Held-to-Maturity, Gross Unrecognized Holding Losses	32	4,620
Securities Held-to-Maturity, Estimated Fair Value	834,574	686,114
Obligations Of U.S. Treasury And Other U.S. Government Sponsored Entities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	370,043	272,301
Securities Available-for-Sale, Gross Unrealized Holdings Gains	1,614	2,968
Securities Available-for-Sale, Gross Unrealized Holding Losses		1,956
Securities Available-for-Sale, Estimated Fair Value	371,657	273,313
Obligations Of States And Political Subdivisions [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	2,616	10,815
Securities Available-for-Sale, Gross Unrealized Holdings Gains	44	281
Securities Available-for-Sale, Gross Unrealized Holding Losses		52
Securities Available-for-Sale, Estimated Fair Value	2,660	11,044
Securities Held-to-Maturity, Amortized Cost	1,992	3,167
Securities Held-to-Maturity, Gross Unrealized Holding Gains	5	7
Securities Held-to-Maturity, Gross Unrecognized Holding Losses
Securities Held-to-Maturity, Estimated Fair Value	1,997	3,174
U.S. Government Sponsored Entities Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	427,300	990,204
Securities Available-for-Sale, Gross Unrealized Holdings Gains	16,995	30,633
Securities Available-for-Sale, Gross Unrealized Holding Losses		9,425
Securities Available-for-Sale, Estimated Fair Value	444,295	1,011,412
Securities Held-to-Maturity, Amortized Cost	818,232	670,403
Securities Held-to-Maturity, Gross Unrealized Holding Gains	14,377	17,157
Securities Held-to-Maturity, Gross Unrecognized Holding Losses	32	4,620
Securities Held-to-Maturity, Estimated Fair Value	832,577	682,940
Other Equity Securities [Member]
Schedule of Investments [Line Items]
Securities Available-for-Sale, Amortized Cost	1,188	938
Securities Available-for-Sale, Gross Unrealized Holdings Gains	877	858
Securities Available-for-Sale, Gross Unrealized Holding Losses	32	43
Securities Available-for-Sale, Estimated Fair Value	$ 2,033	$ 1,753

For an unclassified balance sheet, this item represents investments in debt and equity securities which are categorized neither as held-to-maturity nor trading.

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 13

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 14

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 16

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef

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+ Details

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details

- Definition

This item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-maturity.

+ References+ Details

- Definition

As of the balance sheet date, the excess of fair value over carrying value (amortized cost) of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding gain.

+ References+ Details

- Definition

As of the balance sheet date, the excess of carrying value (amortized cost) over fair value of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding loss.

+ References+ Details